Art of drying



Oct. 5 1926. 1,601,966

H. E. HARRIS ART OF DRYING Filed Jan. 4, 1921 2 Sheets-Sheet 1 [/7 venfor in condensation rad ator. The condensate is accumulated in PatentedOct. 5, I 1 926.

' UNITED STA An'r or nature.

Application fled January 4, 1921. Serial 1110. 484,929,

This invention pertains to the art of drying, and includes both. a

'and .novelmechanism whereby a drying atmosphere is recirculateduntil itattains a certain. saturation with moisture from the ma- ,whereupp'n themo1st air is replaced in whole or in part with fresh and thereupon therecirculation is cone drying atmosphere again attains the desi ed humidcondition, the specified operations of recirculating the atmosand ofreplacing the same in whole or being repeated alterterial undertreatment air, tinued until t phere in part with fresh air nately untilthe material the desired dry condition.

Broadly stated, the invention. consists of means humidity controlledrenewing a drying atmo lated within a closed circulatory path.

In this invention the drying atmosphere is successively circulated intocontact with moist material and with an air heater 'or radiator suppliedwith steam the heat radiated from which is taken up by the drying whichradiation of heat results atmosphere,

of the a chamber Vlth,WhlCh is valve adapted to be actuated by theaccumulated condensate for the operation-of a controlling valve, thelatter a closed circulatory path for the drying atmosphere.

atmosphere circulation of the drying lection of the condensate frornthesteam radiator in a chamber separate from the dir-' such collection ofthe'concirculation of the drying atmosphere being continued until saidat- --mosphere attains a desired degree of saturation by. moisture fromthe material; then for the elxit of the drying atmosphere, inwhole or inpart, and for the volume of fresh air which replaces, in whole'or inpart, the atmosphere culatorypath, densate and the opening a ventingress of a previously circulated an being :positioned in ith thisbrief'statement of "the nature of the invention,- the improvement intheart of drying consists in circulating adrying 1 atmosphere within aclosed path which includes a material-containing chamber an a chamberfor a steam heated radiator acting .toradiate heat for absorption by thedrying and concurrently with such remode of procedure shall haveattained for periodically sphere to be circuwith the steam within theconnected a piston air inlet trollable condensa "stage in atmosphere the001- gives oii desired e rapidity,

quires a d utilizing the acsa uratio valve and at relatively frequentintervalsfor the discharge ofthe condensate and the renewal of the airsuppl gresses, and t e moisture contentofthemm terial decreases,

cu'mulated condensate for the operation of a valve which opens andcloses said vent for the outlet of the humid atmosphere and the ingressof fresh air to the circulatory path.

In respect to the apparatus, the invention includes a controlling valvepositioned in the circulatory path for the drying atmosphere and at apoint adjacent to the valve an exit for the moist atmosphere and aninlet for fresh air, combined with means for collectingthe water ofcondensation generated'by and incidental to the radiation of heat from asteam heated radiator, and a piston valve 0 "eratively connected withsaid controlling va' ve and'with the condensatecollecting means, wherebythe pressure from the steam radiator so acts upon 'the condensate, whena determined volume of said condensate shall have been accumulated, thatthe piston valve is actuated to shift the controlling valve for openingthe moist air outlet and the fresh air inlet, said piston valve beingitself movable to a position for opening an outlet for the collectedcondensate,

result that the accumulated condensate is ejected concurrently with theopenmg of the moist air outlet and the fresh air in et The rate ofgeneration of the condensate within the steam heated radiator is in adefinite ratio to the saturation of the drying 85 atmosphere byabsorption of moisture from the material under treatment, so that thefrequency of operation of -the controlling valve for the moist air exitand the fresh is responsive directly to, or conprimarily by,

te following the radiation of heat from the radiator into suchrecirculating drying atmosphere. Thus at an early the drying wherein thematerial its moisture freely and the drying atmosphere becomes quicklysaturated to the I, 1501366 TES PATENT-OFFICE.

the volume of the.

NEW YORK,ASSIGNOB, MESNE ASSIGNMENTS, '10

011,01 STAMFORD, CONNECTICUT, A COB- xtent with moisture, the condensateis generated and collectedwith comparative as a. result of which thepiston the controllingva-lve are operated but as the evaporation pro-'the drying atmosphere m longer period to attain the desired 11 and thegeneration of the condensate takes place correspondingly 4 more slowly,hence it follows that the controlling valve and 'the piston valve areopened with less frequency, as a result of which the drying atmosphereis recirculated for a relatively longer period of. time within theclosed circulatory path, thereby attaining economy in the steam requiredby the radiaone form of piston valve controllable by the condensateadapted to be .collected in a trap of one form or another. 7 a

A designates a drier of approved construction, having a treating chambera whereinis positioned a series of material-carrying elements hereinshown as trays B, the latter being mounted on a wheeled truck C forintroducing and removing. the trays collectively with reference tosaiddrier.

The drier is equipped with a chamber a within which is positioned asteam heated radiator D composed. usually of coils connected at theirlower ends by a header (1, from which leads a pipe d to a trap E of anyapproved form, said pipe. d being shown as terminating in an upturnedbranch 6 extending into a movable element e of the trap (see Figure 3),although it will be understood that I reserve the right of using anydesired form of steam trap.

Radiator chamber a is in communication with the treating chamber a forthe material on e trays, but as shown in Figure 1, means are providedfor equalizing the flow from the radiator chamber to the trays with- 1nsaid treating chamber, said equalizing means being shown as a pluralityof flues F and a corresponding plurality of dampers F. Theflues vary inlength and are inclined so that the air flows in practically equalvolumes and at the desired velocity across-the trays, the dampers Faffording suitable hand controlled means for regulating the volumes ofair flowing from the radiator chamber to the treating chamber.

G is an eduction flue in direct communication with the treating chambera, said flue providing for the free flow of air from the treatingchamber. The eduction flue ex tends upwardly for a desired distance, andit is in communication with a moist air outlet 9 and a fresh air inleth.

H is an airhcirculating device, shown as 9,

,which is connected a valve rod I leading to a piston valve J. Saidcontrolling valve I normally occupies the full line position of Figure 1so as to close the exit g and the inlet h and to open the communicationfrom the eduction flue G to the blower. Various kinds of valves may beused for control by the condensate accumulated in the trap and operablefor shifting the controllin valve I; but as shown in Figure 3 a pist 11valve is employed in the embodiment of the invention as hereindisclosed. Said piston valve comprises a shell or closing. having anexit branch j"normally open to atmosphere, and a piston J slidablewithin the valve shell. The piston is ati tached to and is movable withthe valve rod 1; said rod being provided with a counterpoise I (seedotted lines in Figure 1), for effecting the positive return of thepiston valve and the controlling valve to their normal positions. To thelower end of valve casing is. attached a pipe is, the other end, ofwhich is coupled to trap E, thus making provision for the admission ofthe condensate from the trap to the chamber below piston J.

The drying atmosphere flow-s normally within a closed circulatory pathconstituted by chamber), flue? G, duct h, blower H, duct k chamber a andflues F, the controlling valve I being in the position shown by fulllines in Figure 1 so as to open com-- munication between flue G and duct72., and't said valve closing the exit 9 and inlet h. The controllingvalve I, and piston valve J, are retained in their normal positions bythe weight'of rod 1 and the count-erpoise 1 said piston valve beingnormally in a position to shut of]? the exit of the condensate throughthe discharge porty". v

In operation, the material is loaded on trays B and the latter insertedinto truck 0, after which the loaded truck is run into the drier untilthe trays are interposed between equalizing flues F and-eduction. flueG. Steam is supplied to the radiator and the blower is started forsetting the drying atmosphere into motion so as to flow within theclosed circulatory path, the speed and capacity of the blower being suchas to cir-- culate the drying atmosphere at the required velocity and inthe desired volume within the drier;

The flow of the, d ing atmosphere into 1 30 contact with the material isattended by'a reduction in the temperature of the drying atmosphere, thelatter giving up some of its' heat and taking up moisture from thematerial' as the 'dryin progresses, said atmosphere havingcbeendieatedto a desired temperature by radiator D. The radiation of heat from andby the steam-heated radiator is/attended by the condensation of steam insaid radiator, resulting as usual in the presflence of water ofcondensation wlthln said radiator, the quantity of which condensatevaries with the moisture evaporated from.

thematerial exposed to treatment by the atmosphere flowing into contacttherewith. At the early stage in the evaporation, certain materials giveofl moisture with com-v parative freedom, and .the drying atmospherethus attains the desired moisture content with comparative rapidity, andconcurrently therewith the heat emanating from the radiator results inthe production of water of condensation or is the conden- 'ruptin themoist drying atmosphere, in whole or in sate in the same relativeproportion. which condensate is collected in the trap until its volumeis such as to lift member e, whereupon the pressure of the steam againstthe liquid condensateforces upwardly the iston valve J, whereby thevalve is lifte to open the exit j for blowing out the accumulatedcondensate. At the same time, rod I- is lifted by pressure against thepiston valve in'order to shift the controlling valve I from the fullline position of Figure 1 to the dotted line position, the eifect ofwhich is to open the exit 9 and inlet h, thereby interthe. closedcirculatory path so that phere attains the desired degreeof saturation.economy of steam for p iod.

more slowly, and there is a corresponding decrease in the generation ofthe condensate 1n theradiator, with the result that the valves I 'Jremain closed for longer periods of time and the drying atmosphere iscircu-' lated within the closed path for. correspondingly increasedperiods of time without re newal of the air. sup 1y, thus effecting J Ieating saidatmdsphere'to a desired temperature during the atenstages inthe evaporation of the material, .in which stages the moisture contentthereof is relatively small so as to neeesitate treatment foracomparatively longer Tlike volume of fresh air.

ing atmosphere attains more or less satura:-

tion of moisture' Again, the piston valve and the controlling valve areby adjustment of a counterpoise such as I so as to'open the controllingvalve I for such a period as to wholly discharge the moist air and re-'place it with fresh air, or said valves may be operated for discharginga certain vol itme of moist air and "replacing it with a It will benoted that in my invention the replacement of the moist air with freshair, in whole or in part, is efiected automatically, and that suchreplacement is dependent upon the generation of a condensate ob tainedby radiation of heat into the drying atmosphere, there being a directrelation between the generation of the condensat and the amount ofmoisture evaporated by? the drying atmosphere from the materia undertreatment. The accumulated condensate is periodically ejected from theapparatus by automatic operation of the piston valve, and this automaticdischarge of the condensate isetfected concurrently with the renewal ofthe air supply, as a result of which the drier is automatically operatedand controlled in a manner to carry on the evaporation at a ratedependent more or less upon the decreasing moisture content of thematerial.

' Having thus fully described the invention, what I claim as new anddesire to secure by Letters Patent is 1. In the art of drying, theprocesswhich consists in circulating a drying atmosphere successivelyinto contact with the material and then with asteam radiator therebyevolving a condensate from the steam supplied to the radiator, andperiodically replacing the moist drying atmosphere with fresh air byutilizing the condensate upon a predetermined volume being collected foropenin and closing a moist air outlet and a fresh air inlet.

2. In theart of drying, the process which consists in circulating adrying atmosphere successively into contact with; steam radiator andthen withmoistmaterial for such a period as results in the atmosphereattainirig a desired humid condition thereby evolv ,ing a condensatefrom thesteam supplied to said radiator, collecting said, condensateuntil a, desired quantity is accumulated, and utilizing theaccumulated-condensate upon a predetermined volume be collected foropening an 'outlet'for the moist atmosphere and an inlet for fresh airwhereby the dry- 'ingatm p ero is by, the, admission of fresh air atintervals dependent upon the humid condition of the drying atmosphere.3. In the art of drying, the process which consists in circulating adrying atmosphere successively into contact with a steam radiator andwith moist material until such atmosphere attains predeterminedcondition thereby evolving from the steam supplied to' the radiator acondensate the generation of whichf-is in a certain ratio to the humidconditionattained by the atmosphere, colecting the condensate in achamber separate from the circulatory path of said drying atmosphere,and utilizing the accumulated condensate upon a predetermined volumebeing collected for interrupting the continuity of the circulatory pathso as to discharge humid air from and admit fresh air to saidcirculatorv path. I

4. In the art of drying, the process which consists inminCulatingadrying atmosphere within a closed circulatory path and into and out ofcontact with material until said atmosphere attains a desired humidcondition, causing the heat transfer from a 'steam radiator into thedrying atmosphere thereby evolving, from the steam supplied to theradiator, a tontlensate the volume of-which is proportional to thehumidcondition attained by the drying atmosphere, periodically opening amoist air exit and a fresh air inlet to thecirculatory path, andcontrolling said exit and inlet by the accumulated condensate after apredetermined volume has been collected.

- 5. In the art of drying, the process which consists in circulating adrying atmosphere -w1th1n a closed circulatory path and into and out ofcontact with material until said atmosphere attains a desired humidcondition, causing a heat transfer from a steam radiator into the dryingatmospheretherebv evolving, from the steam supplied to the radiator,jz'tcon'densate the volume of which is proportional to the humidcondition attained by the drying atmosphere, and peri- ,odicall1yrenewing the dryin atmosphere within said circulatory pathy opening amoist air exit and a fresh air inlet to said c rculatory path, thefrequency of 'such renewal being'dependent upon the time re- I quiredfor the accumulation to a definite volume of the condensate. a p

6, In the art of drying, the process which conslsts 1n circulating adrying atmosphere within" a closed circulatory path and into and .hutofcontact with material until said atmosphere attains a desireddegree ofhug midity, .casuing a heat transfertfrom a steam radiator into saidatmosphere thereby ,evolv:

'ing, from the steam supplied to the radiator a condensate the volume ofwhich is relative to the moisture saturation attained by the dryingatmosphere, periodically renewing the drying atmosphere within saidcir-' culatory path by opening a moist air exit from and a fresh airinlet to said circulatory path, and controlling the opening said exitand inlet by the accumulated condensate upon a predetermined volumebeing collected. d Y I e 7. In the art of drying-the p'rocess whichconsists in circulating a drying atmosphere within a closed"circulatorypath and into and out of contact with material until said atmosphereattains a desired degree of hu-' midity, radiating heat from a steamradiator into said atmosphere thereby evolving from the steam suppliedto the radiator a condensate the volume of which is relative to the.moisture saturation attained by the drying atmosphere, periodicallyrenewing the drying atmosphere, within said circulatory path by openinga moist air exit from and a which consists in; periodically renewing adrying atmosphere circulating within a closed path by opening a moistaire'xit'from and a fresh 2.11 inlet to said circulatory path, radiatingheat into said drying atmosphere by. a steam radiator thereby evolvingfrom the steam a condensate, collecting said condensate in a chamberseparate from the -eir-' culatory path, controlling the opening of saidexit and inlet periodically .by pressure supplied to said condensateupon a predetermined volume being collected, .and discharging theaccumulated condensate concurrently with each renewal-of said dryingatmosphere.

9. In the art of consists in circulating a drying atmosphere within aclosed circulatory path having a fresh air inlet and a moist a1r exit,radiat' drying,the process which ing heat into the drying atmospherefrom a steam radiator collecting the condensate.

evolved from the steam supplied to the 'radiator in achamber separatefrom the circu latorypath, periodically opening the exit from andinlet.to said circulatory path by the collection of a predeterminedvolume of water of condensation, a deter ed volume of the condensatecollected within said. chamber, whereby moist air is discharged fromandfresh air admitted to saidcircu latory path at desired-intervals forrenew-f ing said drying, atmosphere, and discharging the condensateconcurrently-with said renewal of the drying atmosphere-,5; v

10. In a drier, the combination of means forming a circulatory pathhaving a moist air [exit anda freshair inlet, said means includ;

ing a material chamber and a chamber hays in therein a steam radiator,means for cir-' a materialchamber and a chamber having therein a steamradiator, a moist air exit and a fresh air inlet for said circulatorypath,

a, valve normall closing the exit and the inlet and establis ing a pathfor the flow of the drying atmosphere within said closed circulatorypath, means connected with said radiator for collecting a condensatefrom the steam supplied to the radiator, and means operable by thevolume of collected condensate for shifting said valve .to open theexitand the inlet whereby the drying atmosphere is renewed within thecirculatory path. I I v 1 12. In a drier, the combination of means forcirculating a drying atmosphere, means forming a circulatory path whichincludes amaterial chamber and a chamber having therein a steamradiator, a moist air exit and a fresh air inlet for said circulatorypath, a valve normally closing the exit and the inlet and establishing apath for the flow of the. drying atmosphere within said closedcirculatory path, means connected with said radiator for collecting acondensate from the steam supplied to theradiator, a separate valveoperable by a collected volume of the collected condensate for openingan exit through which the condensate is ejected, and operativeconnections between the first valve and the second valve whereby thefirst named valve is controlled for renewing the supply of dryingatmosphere within the 'cir- 'culatory path concurrently with thedischarge of said condensate.

13. In a drier, means forming a circulatory path having a moist air exitand a fresh air inlet and including also a material containing chamberand a chamber having therein a steam radiator, means for circulating adrying atmosphere within said circulatory path, a valve normallyshuttingoff the escape of the atmosphere through the exit and the admission offresh airthrough the inlet, means connected with said radiaton forcollecting a condensate from the steamsupplied to said radiator, meansfor effecting'the discharge periodically of the condensate by a colected volume of said condensate, and means for controlling the firstnamed valve concurrently with the .discharge of the condensate wherebythe drying atmosphere is renewed and the accumulated condensate isejected.

14. In: a drier, means forming a circula- "tory path having a moistairexit and a fresh air ,inlet and including also a material containingchamber and a chamber having therein a steam radiator, means forcirculating a drying atmosphere. within said circulatory path, a valvenormally shutting oif the escape of the atmosphere through -theexit andthe admission of fresh air .the exit and discharging said collectedcondensate, and means for controlling the first named valve by saidpiston valve for effecting a renewal of the drying atmosphereconcurrently with the discharge of the condensate. i

15. In a drier, the combination of means having a circulatory pathhaving a moist air a valve for normally closing the exit and the inlet,means for circulating a drying atmosphere within said, closedcirculatory path,

. and means for automatically controlling said valve to periodicallyopen the exit and the. inlet for renewing the drying atmosphere withinsaid closed circulating path.

' exit and a fresh air inlet and inclu-din amaterlal contalmng chamberand an a1r eater,

16. In a drier, the combination of means for circulating a dryingatmosphere within means forming a definite circulatory path,

said path having a moist air exit from and I.

a fresh air inlet to said circulatory path, a valve positioned fornormally shutting ofi the exit of moist air from and the inlet of freshair to said path, and valve controlling v means controllable byand'responsive to a desired moisture content of the drying atmospherefor periodically actuating said valve for efi'ecting a renewal of thedrying atmosphere. I I

17; In a drier, the combinatlon of means for circulating a dryingatmosphere withm means formin a definite circulatory path, said pathhaving a moist air exit from and a fresh air inlet to said circulatorypath, means for normally closing said exit and inlet, and humiditycontrolled means for actuating said closing means to open e exit and theinlet'upon the drying atmos here attaining a desired moisture vcontent wereby the drying atmosphere is periodically renewed within saidcirculatory path.

18. In a drier, the combinatlon of means for circulating a dryingatmosphere within 'a closed circulatory path, andhumiditycontrolledmeans for periodically replacing said atmosphere with fresh air.

19. In .drier, the combination of means for circulating within a closedpath a dryingatmosphere until the same attains a de sired degree ofsaturation, and means exposed to the flow of said drying atmosphere andresponsive to a predetermined degree consists in circulating a dryingatmosphere within a closed circulatory path until the atmosphere attainsa desired degree of saturation and periodically renewing the dryingatmosphere by' replacing said atmosphere Within the circulatory pathwith fresh atmospheric air, the frequency of such periodic renewalsbeing dependent upon the degree 0f saturation of the atmospherecirculating within said closed path.

In testimony whereof, I have hereto signedkmy name this 22nd day ofDecember,

1920. HOWARD E. HARRIS.

